Structural fuses are known for use in homes, buildings and other structures for dissipating stresses in the structural connections and frames upon seismic, wind or other loads on the structures. For example, the Yield-Link® structural fuse from Simpson Strong-Tie, Pleasanton, Calif., may be used at a connection of a beam to a column so that, when loads on the structural connection reach a threshold, the structural fuse yields to dissipate energy without damage to the beam or column. Thereafter, the damaged structural fuse may be removed and replaced without having to otherwise repair the connection.
A typical structural fuse includes a base and a plate welded orthogonally to the base. The plate may include a midsection having a smaller diameter than ends of the plate, the midsection designed to be the area where yielding occurs. In use, the base may be bolted to a column. A first surface of the yield plate may rest against a surface of the beam, with an end of the yield plate bolted to the beam. A planar buckling restraint plate (BRP) on a second surface of the yield plate, opposite the first surface, may be bolted through the yield plate and into the beam to prevent buckling of the plate under compressive loads. Spacers may be provided in the smaller diameter midsection of the yield plate to evenly distribute loads on the plate and the BRP, when the BRP is bolted to the beam.
Currently, the fuse base, fuse yield plate, buckling restraint plate and spacers are all formed from different pieces of steel, each having different properties. Moreover, welding of the fuse base to the fuse plate needs to be a complete joint penetration (CJP) weld, which are difficult welds to perform and subject to imperfections. Even if done correctly, the weld is less ductile than the other portions of steel in the structural fuse, and can abruptly fail before yielding of the structural fuse at the midsection.